This research proposal is designed to evaluate several immunologic observations noted in our previous studies of systemic lupus erythematosus (SLE). We plan to examine the possible role of cell mediated immunity in the pathogenesis of the characteristic cutaneous lupus lesion, employing lymphocyte stimulation studies of discoid lupus erythematosus (DLE) and SLE patients with and without cutaneous lesions. These lymphocytes will be incubated in the presence of native DNA and ultraviolet light denatured DNA and positive lymphocyte stimulation will be correlated with the presence or absence of cutaneous lupus lesions. The cutaneous lupus lesions will be evaluated for the presence of T cells employing a fluorescein conjugated anti human T cell antisera. Ultraviolet light denatured DNA sensitized guinea pigs will be challenged with chronic ultraviolet light exposure in an attempt to induce cutaneous lesions similar to those found in human lupus. The specificity of the guinea pig, delayed hypersensitivity response to DNA as well as the possible role of ultraviolet denatured DNA in the production of renal nephritis will also be examined. The antibody specificity of serum IgE and IgM and SLE patients to various nuclear and cytoplasmic components will be determined. Finally, the possible relationship between DLE and SLE will be examined.